Ab Initio Large Unit Cell Calculations Of The Electronic Structure Of Alp Nanocrystals

Abstract

Ab – initio restricted Hartree – Fock (RHF) method coupled with the large unit cell method (LUC) is used to investigate the electronic structure of AlP nanocrystals core part with different sizes. Energy gab and valence band width are obtained from the electronic structure calculations. Final electronic energy levels are used to draw electronic density of states distribution. The results are compared with available experimental data and the theoretical results of other investigators. Results revealed that electronic properties converge to some limit as the size of the LUC increases and that the 128 atom LUC is near to the bulk of these materials . Increasing the size of LUC also resulted in an increasing of energy gap and increasing valence band width. The calculated lattice constant shows decreasing trend as the nanocrystal increases in size that converges to 0.523 nm which is in good agreement with experiment. The present method can be used to investigate the electronic structure of bulk, surface and nanocrystals